1. Field of the Invention
The present invention generally relates to the field of digital video processing, and more particularly, to methods and systems for providing an intelligent and efficient camera motion estimation for video stabilization.
2. The Relevant Technology
Video (moving pictures or sequence of images\frames) captured by ‘cameras mounted on a moving vehicle or a robot’, ‘Hand holding, light weight video camcorders or mobile phones’ suffers from ‘JITTERS’ or ‘SHAKES’. Video normally consist of motion, including object motion, such as a bird flying, and camera motion, such as camera panning, zooming, and tilting. Other than natural motion of an object or camera, the video camera may record unwanted motion. The term “unwanted” usually refers to camera motion frequently resulting from hand jittering or from physical movement of a person capturing video. Other unwanted motion may include, for example, wind shakes a mounted camera or a vehicle carrying a camera traverses rough terrain etc. This unwanted motion might result in blurred or displaced frames thereby degrading the quality of video.
Holding a camera stable, while capturing a video is almost an impossible task. Video captured with such unavoidable camera shakes will result in annoying visual shakes/jitter in video. So some means to remove such unwanted camera motion in video becomes inevitable. Video stabilization is such a technology that avoids jitter in video either while capturing or after capture. Camera motion estimation is important and critical for any efficient video stabilization.
Camera motion can be estimated with mechanical systems (using motion sensors) and software systems (by digital signal processing). Mechanical systems for camera motion estimation are more robust compared to the software based counter parts. But mechanical systems are costly and increase the physical size of the system. Range of motion, the mechanical stabilizers can correct, is limited by the movement of lens system and hence presents some disadvantages. Also, the reaction time is limited by physical factors and cannot be too quick. On the other hand the amount of motion that can be corrected is adjustable in software-based solutions. Software solutions have the advantage that they facilitate compact designs (More demand for sleek, compact and handy devices) and they make any further up-gradations easier. Software solutions offer much flexibility and reusability for video stabilization. This shows a that software-based solution for hand held cameras has advantages over the mechanical systems.
With the convergence of technology and applications, “Camera phones” with full-fledged video processing capabilities are expected to play a predominant role in the next generation communications dominated by Video. There has been an ever-increasing demand for “sleek camera phones” and with such sleek models it becomes very difficult to hold them stable in hands to capture video. State of art solutions for video stabilization is suffering from its in-ability to process video data in real-time on handheld and battery operated devices. Camera\Global motion estimation for a video sequence requires robust estimation of global (or camera) motion in spite of various disturbances like high local motion; crossing objects, capture noise, illumination changes, etc. Present technologies still suffer from trade-offs in accuracy and complexity. Hence the “video stabilization” to remove the inevitable un-wanted jitter resulting in the video captured with such handy devices, becomes mandatory. This in turn demands for camera motion estimation either by sensing the movement of the lenses by motion sensors or by studying the content motion from frame to frame in software.
Thus there is a need for a fast and accurate, less complex camera motion estimation technique for practical implementation of video stabilization on mobile devices that overcomes the afore-mentioned shortcomings.